Chimpanzees and Bonobos Use Hugs, Kisses and Friendly Pats to Keep the Peace, Just Like Humans, a New Study Suggests

Since all three ape species diverged from a common ancestor that lived roughly six million to eight million years ago, the findings hint that friendly touching to diffuse tension has deep evolutionary origins

Sarah Kuta | Daily Correspondent

July 27, 2026 10:00 a.m.

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From hugs and handshakes to high fives and fist bumps, humans routinely use physical touch to comfort one another and reinforce social bonds. Now, new research suggests that our ape cousins behave in similar ways.

Semi-wild bonobos and chimpanzees hug, hold hands and pat each other during stressful situations. These friendly touches may help ease tension and potentially prevent conflicts from arising among group members, scientists report in a study published July 22 in the journal Proceedings of the Royal Society B.

“Physical closeness is a really powerful way of managing stress,” study co-author Zanna Clay, a primatologist at Durham University in England, tells Science News’ Meghan Rosen.

Beyond offering new insights into the apes’ behaviors and social dynamics, the findings also hint at an evolutionary explanation for our own peacekeeping tendencies. Humans, bonobos and chimpanzees diverged from a common ancestor species that lived roughly six million to eight million years ago, so friendly touch as a means of diffusing tension might be an ancient behavior that evolved long ago.

“Comparing bonobos and chimpanzees—our two closest relatives—offers fascinating insight into the evolutionary roots of social behavior and how they, and we, manage tension, competition and cooperation,” study co-author Jake Brooker, a primatologist at Utrecht University in the Netherlands, says in a statement.

While studying bonobos and chimpanzees in south-central Africa, researchers observed the animals consoling their peers after stressful situations. But they also noticed a surprising behavior: The animals seemed to be using friendly physical contact proactively, making gentle touches during tense moments before anyone became upset.

To study the phenomenon more directly, scientists conducted experiments with five groups of bonobos or chimpanzees living at sanctuaries in the Democratic Republic of the Congo and Zambia. Over several months, they ran 60 sessions of a previously developed feeding task called the peanut swing.

They sounded an alert to tell the animals about incoming snacks, filled a bamboo trough with peanuts, then swung it over a fence so that the tasty morsels would be distributed evenly across a small area in front of the primates. This created an exciting situation—yummy treats being delivered right to the apes—but also a stressful one, since the peanuts were a highly valuable but limited resource. The scientists documented the animals’ behaviors before, during and after peanut distribution.

A pattern emerged from those observations: Bonobos and chimpanzees who engaged in friendly contact in the few minutes before peanuts rained down were more likely to munch peacefully alongside each other once the snacks hit the ground. The proactive physical touches included hugs, kisses, pats and love bites, as well as “reassurance trains,” in which several animals embraced each other from behind in a line, per the statement.

Overall, these behaviors seemed like a “rallying cry” of sorts, similar to a sports team huddling up before a big game, Clay tells BBC News’ Helen Briggs. “It’s like a ‘we’ rather than a ‘me.’”

The link between preemptive touch and harmonious feeding was strongest among the groups that had high levels of social tolerance, or a willingness to share space and cooperate without conflict. In groups with more authoritarian leaders, however, the pattern “disappeared,” Clay and Brooker write in the Conversation.

In the bonobo groups, females were more likely to exchange friendly physical touches with other females, a finding that aligns with the species’ matriarchal society. In the chimpanzee groups, males were more likely to touch other males, which the team thinks reflects the species’ male-dominated hierarchies.

The researchers were surprised to see chimpanzees placing their fingers, hands and other body parts inside each other’s mouths during stressful situations—a risky move for a species prone to violence. The animals also held one another’s genitals. With both behaviors, the scientists suspect that the animals were intentionally making themselves vulnerable to signal trust.

“You only offer a risky contact if you are confident the other animal won’t bite,” the researchers write in the Conversation. “And this communicates something important about how you see the relationship.”

Chimpanzees are known for being more aggressive than bonobos. But the experiments suggest that both species use touch in a similar, tension-easing way, which suggests the behavior might have deep evolutionary roots.

“This strengthens the likelihood that our shared ancestors also used the same mechanisms to decrease social conflict,” Julie Teichroeb, a primatologist at the University of Toronto in Canada who was not involved with the study, tells Nil Kӧksal of CBC Radio’s “As It Happens.”

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.